Field of the Invention
The present invention relates to a water-based ink for ink-jet recording, an ink cartridge, an ink-jet recording apparatus, an ink-jet recording method and a method for evaluating water-based ink for ink-jet recording.
Description of the Related Art
As an ink usable for ink-jet recording, there is proposed a water-based pigment ink containing a pigment and water (see, for example, Japanese Patent Application Laid-open No. 2004-231711).
Regarding the above-described water-based pigment ink, when an attempt is made to improve the storing stability, the optical density (OD value) is lowered in some cases. In view of this situation, an object of the present teaching is to provide a water-based pigment ink for ink-jet recording capable of realizing both of high optical density (OD value) and high storing stability.